Figure 5. Incorporation of ¹⁵N-labels into C2 (9) in the cells.

[¹⁵N₂]Int-C’2 (4′) or [¹⁵N₂]Cyclic-C’ (7′) were repetitively administered to the medium at 5.0 μM approximately every 10 days for 31 days (0-, 10-, 20- or 21-day). (a,b) Isotope patterns of C2 (9) at day 0 and day 31. The abundance of m/z 474 is shown as 100%. The theoretical natural abundance of m/z 476 (12.4%) is shown as a dashed line. (c) [¹⁵N₂]-labeled ratio of C2 (9).